An Overview of MEMS and non-MEMS High Performance Gyros
Let us review the story of one of the most complex handheld sensing instruments built by mankind, namely gyroscopes.
This story started two centuries ago with the “Machine of Bohnenberger”. The first gyroscope was made with a massive sphere rotating thanks to three pivoted supports. It can be seen as a precursor of the Foucault Gyroscope. French physicist Leon Foucault first used his famous pendulum (a 28kg brass-coated lead bob with a 67-meter-long wire from the dome of the Panthéon, Paris) to demonstrate the rotational rate of the earth in 1851, and then went on to perfect the measurement using a gyroscope in 1852. In order to grasp the underlying mechanics, one has to imagine that the plane of oscillation of the pendulum remains fixed relative to the distant masses of the universe, while Earth rotates underneath it.
During the 19th century, gyroscopes remained a scientific curiosity. At the beginning of the 20th century, ships were increasingly built with steel, which sometimes resulted in poor performance of the traditional magnetic compass. This limitation of the compass for ship navigation drove the transformation of the gyroscope from the initial prototype device to a real product – gyros became the best solution to indicate the true (geodetic) north within a steel ship. The gyroscope was first patented in 1904 by German scientist and inventor Hermann Anschütz-Kaempfe. Four years later, on the other side of the Atlantic, Elmer Ambrose Sperry patented the same type of device and established the Sperry Gyroscope Company. It is interesting to note that the Anschütz patent was contested by Sperry but, following an expert opinion provided by future Nobel Prize winner Albert Einstein, Anschütz was able to uphold his patent. The products from Sperry Gyroscope had a huge impact during the Second World War, as they were used in a large set of applications such as ship navigation, guided missiles, battery fire control, aircraft artificial horizon, and flight controls. By 1943, over 100,000 people worked for Sperry Gyroscope.
Since the end of the Second World War, gyroscopes have progressed from complex electromechanical devices assembled with more than 100 parts to modern solid-state devices. Starting with ESG (Electrostatic Suspended Gyro), the progress has been enabled by the rapid adoption of new technologies: DTGs since the 1960s, RLGs since the 1970s, FOGs since the 1980s, and MEMS since the 1990s. In the future, other exciting technologies such as cold atom interferometry, integrated optics, and nuclear magnetic resonance may also be used in industrial applications.
Log in with Google